CATION

A European consortium is formed for Cathode Subsystem Development and Optimisation (CATION).

CATION project will last for three years and has started on January 1, 2011. Total budget of the project is 7,19 Million Euros. The research consortium coordinated by VTT Technical Research Centre of Finland comprises of several European collaborators:

  • Wärtsilä Finland Oy, Wärtsilä
  • AVL List GmbH, AVL
  • Topsoe Fuel Cell A/S, TOFC
  • Bosal Emission Control Systems NV, Bosal
  • Centro per lo Sviluppo della Sostenibilità dei Prodotti, UNIGE

Summary for Mid-Term Reporting:

Fuel cells and hydrogen have a potential for reducing emissions of greenhouse gases and air pollutants, facilitating the increased use of renewable energy sources, raising overall efficiencies of conversion. In addition the high temperature fuel cell technology SOFC has the potential for high electrical efficiency, 55-60%, and total efficiency up to 90% for CHP units combined with low emissions. However, the cost and lifetime of SOFC systems is a problem that must be solved before breakthrough on the commercial markets can happen.

In large SOFC systems the cathode subsystem is typically the largest source of auxiliary losses and a major factor decreasing electrical efficiency of the system. The reason for this is that almost all components are based on existing products developed for some other purposes and are not optimized for certain SOFC systems. By making cathode side components from the SOFC system point of view, i.e. optimizing the overall system solutions, significant improvements in terms of costs, reliability, performance and lifetime will be achieved. The CATION is focused on the development of SOFC system’s air side fluid and thermal management and mechanical solutions, i.e. cathode subsystem and individual components. A parallel optimization of the anode subsystem is carried out in the EU funded ASSENT project.

 

The main objective of the CATION is to find optimal process and mechanical solutions for the cathode and stacks subsystems with the aim of having commercially feasible and technologically optimised subsystem solutions ready for future ~ 250 kWe atmospheric SOFC systems. The aspects taken into account in the development are mainly electrical efficiency, controllability, reliability, mass production and cost effectiveness of developed subsystems and individual components.

 

However, to reach this main objective some sub-objectives have to be finalised and the most important ones during the reporting period (M1-M18) were the following:

    ·         To provide modelling input for optimal cathode subsystem layout and choosing the best ones for further analysis. Preliminary sensitivity analysis for several key parameters and reliability analysis for the most promising subsystem will also include (WP1).

 

    ·         To develop components those are optimal for the cathode subsystem and evaluate their feasibility and manufacturing technologies (WP2).

 

    ·         To develop a compact and cost-effective stack subsystem solution where the stack/system interface and related solutions are optimized (WP3).

 

    ·         To design and evaluate the overall cathode subsystem solution which will be developed within this project (WP4).

 

Results and work performed in the reporting period

 

Work package 1: This WP was completed in the reporting period. Steady-state system modeling and reliability analysis were done for several layout concepts. Based on the results the best layouts (the ejector and modular stack structure) were decided and chosen for further analysis. Results were also reported to the other work packages and to the consortium.

Work package 2: The main results were the successful modelling and testing of relevant components for the cathode subsystem. New virtual tools were also developed for optimising the recuperator core. It was proven that two automated assembly processes are possible for HEX core serial production. The cathode ejector and burner concept were tested successfully and tests proved the feasibility of those component for the process concepts given by WP1.

Work package 3: Both the OAM stack (Open Air Manifold) and IPM (Integrated Power Module = hotbox) module have been developed such that they are well adapted to each other in a way that they jointly ensures an improved balance of plant cost especially regarding the cathode energy consumption.

 Work package 4: WP has mainly concentrated on detailed analysis and evaluation between the most promising process alternatives evaluated in WP1, namely concepts 4 (air-in-series) and 6 (recirculation by ejector). While some of the analysis showed practically no inherent difference between the process alternatives, the cathode ejector based circulation was found to be beneficial by others.  This was especially the case with respect to sensitivity towards stack quality deviations, and the operability and controllability of the system. Both of these are very critical aspects especially in large systems having multiple stacks. Additionally, the only major open item in cathode ejector case – the actual operation of the hardware – was proved in WP2 not to be an issue. Hence the approach based on cathode ejector was chosen as the concept to be pursued further.

As part of the objectives for this reporting period, three milestones were met as described in Annex I. These were choosing the optimal system concepts for further study, a decision on the final stack system solution as well as the power range to be tested and the stack module go/no go decision.

The expected final results and their potential impact and use

The original aim of the project was to develop a commercially viable cathode subsystem for a commercial 250 kW SOFC system and manufactured by Wärtsilä and during this reporting period the project has progressed very well. However, Wärtsilä has announced that it will terminate its fuel cell activities and partnership in the project. At the moment the future of the project is therefore open, however, there is planning going on how the project can be continued in a manner that it benefits the rest of the participants, and also the fuel cell community in general.

Additional Information:

Dr. Jari Kiviaho
Project Manager
+358 50 511 6778
jari.kiviaho(at)vtt.fi